Internal-combustion engine



June 14,1927. 1,632,684-

c. TUCKFIELD INTERNAL COMBUSTION ENGINE Filed Jan. 13. 1927 2Sheets-Sheet 1 Fig.7. 5 6

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I C. TUCKFIELD INTERNAL COMBUSTION ENGINE Filed Jan.13. 1927 2Sheets-Sheet 2 Patented June "14, 1927.,

. UNI STATES P CHARLES TUGKFIELD,'OF EAYST ivrotnsnvgnneiAnn."

INTERNAL-COMBUSTION ENGINE.

' Applicationfiled 3 3 13, 1927 Serial gine. will give a considerablygreater H. .P.

output, or the samev output with a much I lighter engine. A furtherobject of the in vention is to obtain the same compression pressure athigh altitudes as at searlevel and to avoid loss of {power and fuelcaused by weak compression. p j I According" to this invention I employa valve positioned in a transfer passage between a compression chamber,which may be the crank case, and a port or ports near the end of thecylinder, whichports are uncovered by the piston at theend-ofits outward stroke. the valve being so constructed that it is subject on oneside to-the pressure in the. cylinder, when the ports are open,

and subject on the other side tothe atmosphere and a'regulating spring,the spring i normally holding the valvein such position that thetransfer passageisgopen until the pressure in the cylinder overcomes theforce of the spring and atmospheric pressure to movethejvalve to closethe transfer passage.

My invention will be clearly understood from the following descriptionaidedby the examples shown on the annexed drawings in which; v 7

Figure 1 is a sectional elevation (more or less diagrammatic) of afourstroke engine constructed according to this invention. Figure 2 isa'detail view of a modified construction of piston valve. i a

Figure} 3 is a sectional elevation (diagrammatic) of a two stroke enginewith a. portionof a second cylinder and piston showing my inventionapplied. It is to be understood that. for sake of clearnesethe secondcylin'de-r is shown at the/side but in practice wouldbein front, thatis! to say, would have the piston rodconnected tothe same crank shaft asthe first piston. i

- 1 is the cylinder, 2 the piston, 3 the crank case, 4 the air inletvalve, 5 the fuel inlet valve and 6 the exhaust valve, all of, which areof ordinary construction. In one em- Y bodiment of the invention a valvecasing 7 is attached to the cylinder, which casing has a passageway 8connected at one end with a 160,957, and in Great Britainpctober 5,1925.

port or ports 9 arranged near the endof the cylinder 1 and adapted to beuncovered by the. piston 2 when it-reaches the end .of its outwardstroke. The other end of the passage way 8 is connected. by a pipe 10 tothe. crank case 3. In the casing 7 is a passage. 11 whichextendstransversely of the passage way 8 and is connected at one end tothe peesage-11 at another point byjan opening12. The other endff. thetransverse passage 11 is opento the atmosphere. V

In the transversepassagell is positioned the piston valve 13abutting'against a spring 14', the pressure of whichjcan'be adjusted Inthe pistonvalve13 is aport 16 which normally so positioned as to putthat por-' tion'ofthe passageway. 011.0118. side of the transversepassage into communication with TENT} e u.

by any suitable mcans, suc'has a screw cap 1 the part of the passagewayon the opposite 1 side of said passage. Such port may consist of a holebored transversely ofthe piston valve 13 as shown in Figures 1 and?) ormay be in the form ofa circular: groove in the periphery of the valve13, asin Figure 2.

When the valve 13 is .in its normalposition the .port 16 is in.alignment with the passage way'8 so that the port 9 is open to the crankcase 13 and the spring 14 is adjusted to the pressure required in thecylinder 1. j

Inthe case of four stroke engines as shown in-Figure 1 the fuel inletvalve 5 is arranged to close a little earlier than is usual and thecrankcase3 is made comparatively air-tight so that onthe upward movementof the piston 2 air will be drawn in through the nonreturn valve 4.andycompressed in the crank case 3 on the outward stroke. I

, The operation of a four-stroke engine (Figure 1) :is as follows -Arich mixture.

is introduc ed into the'cylinder 1 through the fuel inlet valve 5 in theusual way; 111 the outward movement of the piston 2, just before thepiston uncovers the port 9, the inlet valve, 5 closes and 'onthe furtheroutward movement of the piston 2theport '9 isun covered and the aircompressed in the crank case 3 by. the outward movement of the pistonpasses through the pipe 10, passage way 8 and port 9 into-the cylinder 1until the pressure above the piston I valve 13 reaches the requiredpressure determined by the spring 14;. Any increase of pressure beyondthis point will,,facting .through the 13 force said valve outwardsagainst the no opening 12 onthe. end. of the piston valve spring 14 andmove the port 16 out of alignment withthe passage way 8 and prevent thepassage of any more air into the cylinder 1. At the end of thecompression stroke of the piston. the fresh air, which has now mixedwith the charge admitted through the valve 5, forms an explosivemixture, at either a higher compression pressure or filling a largercompression space at normal pressure, whichever system of superchargingis preferred.

Bythis means constant compression at varying altitudes, with its greatfuel saving and extra speed, will be gained attained, since although thepressure in the crank case 3 may be high, the valve 13 will prevent thepassage of any excess of air into the-cylinder 1. This is all that isrequired for road and water locomotion, but where great heights areattained, such as in aeronautical machines, the spring 141 would be setaccording to the level at which the machine is to travel, or the springmay be adjusted by the apparatus set forth in Tucktields British PatentNo. 129,663. and also in Tuckfields British Patent No. 171,533. In thelatter case the device can be attached tothe valve case 7 so that thepressure of its expansion added to .the pressure of the spring 14.

If a multi cylinder engine is used, each cylinder 1 should have its. ownair compression chamber in the main crank case and duplex pistons of asize proportioned to the extra air required may be used.

hen each cylinder 1 has its own separate crank case or air compressionchamber 3 every alternate stroke of'the piston is a scavenge stroke andthis will. assist in effecting a further saving in fuel, so that it willbe seen that by this system all the advan: tages of supereharging aregained practically without the addition of any weight, space orcomplications.

' lVhere no scavenging stroke is employed the mixture might. beintroduced intothe crankcase 3 as well as the cylinder 1, but I preferto use air, in the former, because where no scavenging stroke is usedone crank case 3' and-valve -13'-would=provide superclmrge-'for twocylinders", but, it would require a three way cock 'and means foractuating it.

111 applying"the invention to atwo stroke engine-I preferably providethe usual inlet p orts,but regulate the exhaust by a mechanicallyoperate'dwalve (3, as shown in Figure 3. the supercharging valve 13acting in a similar manner to that already-described in relation to afour strokeengine.

I- may employ a cylinder of enlarged bore at its lower end and fittedwith a'suitable piston working in tandem with the main piston, in whichease I'may use air in both the crankcase andin' the enlarged part of thecylinder and mix it with fuel before it passes through the regulatingvalve 13 on its way to the ports 9 in the cylinder 1.

I may, as shown in Figure 3, employ the enlarged end 1 of one cylinder 1as a pump for scavenging another cylinder and the crank case 3 forcharging and supencharging, or vice-versa, in which case I employcross-over pipes 17, 17 and non-return valves 18, 1S connectingtheadjacent cylinders 1, 1

18 is the carburetter.

In this construction it is necessary to enlarge the bore of only a smallpart of the cylinder in order to enable the engine to operate as atwo-stroke engine and to have the same compression pressure atelevations of twenty thousand feet, or higher, as at sea-level, as wellas tooperate with light or heavy oils, and to prevent loss of power andfuel caused by weak compression in heavy vehicles such as lorries,omnibuses and touring cars.

It will be seen that with this supercharger, not only is the risk ofdamaging gearing, which so frequently occurs in blow ing superchargers(caused bythe enormous velocity required of them), avoided, but also alarge part of the power expended by them is saved.

lVith this system the unexpired compres sion is returned to the piston,that is to say, if only a small quantity of the superchargc is takeninto the cylinder 1, the balance is left in the crank chamber 3 where isreturns to the piston 2 the energy stored in it on its compression.

What I do claim as my invention and desire to obtain by LettersPatentis 1. An internal combustion supercharging engine comprising a cylinderhaving a port in its wall, a piston working in said cylinderandoperableon its outer stroke to open said port, an air compression chamberconnected to the outer end of said cylinder. a transfer passage betweensaid compression chamber and said port, a valve controlling saidtransfer passage, and yieldable means tending to maintain said valve inopen position to establish communication between said pressure chamberand said port, said valve having a portion subject to the pressure insaid transfer passage for causing said valve to move into closedposition when the pressure in the transfer passage is sufficient toovercome said yieldablc means.

2. An internal combustion supercharging engine comprising a cylinderhaving a. port in its wall, a piston working in said cylinder andadapted on its outer stroke to open said port, an air compressionchamber connected to the outer end of said cylinder, a valve casingassociated with said cylinder having a passageway connected at one endto said port and its other end connected to said compression chamber,said casing'also having a passage open at one end to the atmosphere andextending tranversely of said passageway and also having an openingbetween said passageway and the inner end of said transverse passage, avalve movable in said transverse passage having-a port adapted tocoincide withsaid passageway, said valve having its inner end subjectthrough said opening to the pressure in said passageway, andhaving itsouter end subject'to the at mos here a s urin actin on the atmos hereside of said valve to normally maintain its -port in coincidence withsaid passageway,

i and means for adjusting the pressure of said ,spring on said valve;

3-. An internal combustion supercharging engine, comprising a cylinderhaving inlet and exhaust valves adjacent its inner end and having itsbore enlarged adjacentits outer end, that part ofsaid cylinder ofsmaller bore having a port in its wall adjacent its outer end, meansclosing the outer end of that portion of said cylinder oflarger bore, aduplex piston working in said cylinder and operable on its outer stroketo open said port and compress air in that part of the cylinder oflarger bore, means comprising a non-return valve for admitting air tothat part of the cylinder of larger bore a conduit connecting that partof said cylinder of larger bore and said port, a valve controlling thepassage of air through said conduit,

yieldable means acting on said valve and normally holding it in openposition, and

means for adjusting the pressure of said yieldable means onsaid valve,said valve being subject to the pressure in said conduit and beingmovable into closed position when said pressure is sufiicient'toovercome'said yieldable means. y

4. An internal combustion supercharging engine comprising a cylinderhaving a port inits wall, a compression chamber connected to the outerend of said cylinder, a piston working in said cylinder operable on itssaidvalve to assist in moving it into open position, yleldable means 111said caslng acting upon the atmosphere side of said valve and normallyholding said valve in open position, said casing also having a secondpassage between said valve and said port through which pressure in saidcylinder may act upon saidvalve andmove it into closed position whensuch pressure is suflicient to overcome the ressure of the atmosphereand of said yieldaiile means upon said valve.

In testimony whereof I my hand.

' CHARLES TUCKEIELD.

have hereunto set

